Use two digits for ext part of Oracle 23 version string

lib/oci8/oci8.rb

@@ -349,7 +349,7 @@ def inspect
   # @see OCI8.oracle_client_version
   # @return [OCI8::OracleVersion]
   def oracle_server_version
-    @oracle_server_version ||= OCI8::OracleVersion.new(oracle_server_vernum)
+    @oracle_server_version ||= OCI8::OracleVersion.new(oracle_server_vernum, is_server_version: true)
   end
 
   # Returns the Oracle database character set name such as AL32UTF8.

lib/oci8/oracle_version.rb

@@ -61,7 +61,7 @@ class OracleVersion
     #   oraver.port_update # =>  0
     #
     # @return [OCI8::OracleVersion]
-    def initialize(arg, minor = nil, update = nil, patch = nil, port_update = nil)
+    def initialize(arg, minor = nil, update = nil, patch = nil, port_update = nil, is_server_version: false)
       if arg.is_a? String
         major, minor, update, patch, port_update = arg.split('.').collect do |v|
           v.to_i
@@ -91,6 +91,7 @@ def initialize(arg, minor = nil, update = nil, patch = nil, port_update = nil)
                 else
                   (@major << 24) | (@minor << 20) | (@update << 12) | (@patch << 8) | @port_update
                 end
+      @is_server_version = is_server_version
     end
 
     # Compares +self+ and +other+.
@@ -127,7 +128,11 @@ def to_i
     #
     # @return [String]
     def to_s
-      format('%d.%d.%d.%d.%d', @major, @minor, @update, @patch, @port_update)
+      if @is_server_version && @major >= 23
+        format('%d.%d.%d.%d.%02d', @major, @minor, @update, @patch, @port_update)
+      else
+        format('%d.%d.%d.%d.%d', @major, @minor, @update, @patch, @port_update)
+      end
     end
 
     # Returns true if +self+ and +other+ are the same type and have